Lifting jack



A. RISSANE LIFTING JACK Filed Sept. 20, 1938 Dec. 5, 1939.

INVENTOR.

w m n A AUGUST PISSANE E 1112; 122 2 5Mm Patented Dec. 5, 1939 UNITED STATES PATENT OFFICE 6 Claims.

This invention relates to lifting jacks, more particularly for the purpose of lifting one end of a motor vehicle although it may be constructed in varioussizes and of relative strength to serve almost any purpose to which lifting jacks are applicable.

The principal object of the said invention is to provide a very simple, stable, strong and powerful device for the purposes, having but few parts, capable of very'rugged construction, and being decidedly dependable in its operation and easy to operate.

A further object is to provide such a device which while having a considerable latitude of lifting movement, calls for a minimum of clearance for the jack in its application to the object to be moved.

The said invention also. provides for a very efiicient support of the weight applied to certain moving parts of the device in a manner minimizing any tendency to bind under pressure or in operation, or to be forced out of alignment; and,

still further, the said invention provides for the relieving of the operating screw of the device from such lateral or angular pressure as may tend to bend the said screw, or to add extraneous forces to the simple lifting function of the said operating screw.

The said invention further contemplates the provision of a very simple and eflfective means for permitting rapid initial adjustment of the jack to the work prior to its performance of the actual lifting of the said work.

Still further objects or advantages subsidiary 5 to the aforesaid objects, or resulting from the construction or operation of the invention as it may be carried into effect, will become apparent as the said invention is hereinafter further disclosed.

In carrying the said invention into effect, I may provide an elongated track forming a part of the jack assembly, a fixed guide bar thereabove and parallel to said track, an operating screw parallel to but independent of the guide bar, said screw being threaded in opposite directions from opposite ends toward the medial portion thereof, a pair of blocks slidable on the guide bar and engaged for movement therealong by the said operating screw, trunnion members on the said blocks provided with wheels traveling on the said track, and toggle arms extending from'said trunnion members to a common pin carrying the table of the Jack, whereby pressure on said table is transmitted through said axle members to said wheels and from thence to the track and whereby the operation of the said screw in one or other of the directions will effect the toggle action of the said members for the raising or lowering of the table. It is preferred that the blocks be of such construction that manual raising of the toggle arms, such as by upward pressure applied to the under side of the table, will eflect and disengage the said blocks from the thread of the operating screw to permit rapid raising of the said table to the work independently of the said screw. All of which is more particularly described andascertained hereinafter, by way of example, having reference to the accompanying drawing, wherein:

Figure 1 is an elevation of the improved jack;

Figure2 is a plan of the same;

Figure 3 is a fragmentary detail section taken on a plane indicated by the line 33 in Figure 2;

Figure 4 is a similar view to Figure 3 showing the modified form of the parts; and

Figure 5 is a detail cross section taken on a plane indicated by the line 5-5 in Figure 4;

Similar characters of reference indicate similar parts in the several figures of the drawing.

Referring first to Figures 1, 2, and 3, I0 is an elongated track or guide member of a rigid nature bent upwardly at one end to provide the end wall II and also having inverted U-shaped bridge I2 intermediate its length through which passes a second guide member in the form of a. rod l3; this rod extends substantially the length of the said track and is secured to the bridge 12 as by welding or in any other desirable manner.

I4 is a feed screw extending above and parallel to the guide rod l3, and rotatively secured at one end I5 in the end wall ll of the said track, the said screw being provided with a right-hand thread l6 throughout the main right-hand portion of its length and a left-hand thread through the main left-hand portion thereof. I8 is a suitable coupling on the free end of the said feed screw for permitting attachment of a suitable operating lever or handle thereto to effect rotation of said feed screw.

l9 and 20 are end members in the form of blocks threaded at 2| and 22, respectively, to engage the left and right-hand threads of the operating screw, the lower part of each block slidably fitting on said guide rod IS in such manner that the axial alignment of the threaded holes 2| and 22 of the said blocks with the axis of the operating screw is at all times maintained, and relative tilting of the blocks to the screw and a consequent tendency to bind under conditions of operation thus prevented.

The said blocks l9 and 20 are further provided with pins or trunnions 23 and 24 extending laterally thereof and carrying wheels or rollers 25 and 26, which wheels travel on the upper surface of the said track Ill. The said trunnions 23 also carry the outer ends of a pair of toggle arms 21, and the pins 24 similarly carry the outer ends of another pair of toggle arms 28, the inner ends of all of which arms engage a common cross pin 29 which freely carries the table 30 of the jack.

In its simpler form, the wheels 25 and 26 may be omitted while still retaining some of the advantages of the construction referred to, the guide rod l3 in such case being charged with the weight supporting function which the said wheels more desirably assume in the construction already described. Or the guide rod l3 may be omitted and the wheels engaging the track retained.

It will be understood that the guide rod i3 may be of any cross sectional form and not necessarily round as shown, and where the said.

wheels 25 and 26 are not used I prefer to use a cross section of guide rod other than round, in order to obviate any tendency of the blocks l8 and 20 to rock sideways about the axis of the said guide rod. Any such tendency in the previously described arrangement is obviously overcome by the contact of the said wheels 25 and 26 with the track member Ill.

It will be seen that, in the construction described, the feed screw is only subjected to the end thrust imposed thereon by the tendency of the toggle arms to spread under weight or pressure imposed on the jack table 30, and the said feed screw, therefore, is not subjected to any bending stresses or downward thrust, due to the fact that such downward thrust is imposed on the track III through the wheels 25 and 26; and any tendency of the blocks l9 and20 to tilt about the axes of the said wheels is prevented by the sliding engagement of the said blocks with the guide rod i3. Consequently, only one end of the said feed screw need be secured, as in the end wall ll of the track member, to prevent longitudinal movement of the feed screw.

The arrangement described thus far, in its simple form, required the operation of the feed screw to raise the table of the jack to the work as well as for the actual raising of the work, and this in many cases is not undesirable; but the invention readily admits of the incorporation of feed releasing means in the said blocks, or their equivalent, to permit adjustment of the table height independently of the operation of the feed screw where this feature is thought necessary or desirable.

Such an arrangement I have illustrated in Figures 4 and 5, wherein it will be seen that the block, in this example, is formed in two parts, namely, a base member 3| slidable upon the guide rod I3 and having an upwardly projecting central portion 32, and an upper end cap member 33 of inverted U-formation in cross section straddling and vertically movable on the upwardly projecting portion 32 of the said base member 3|. This vertical movement of the cap member is guided by pins 34, extending upwardly through the cap member from the base member 3|, and limited by suitable stop means 35 at the upper ends of said pins 34.

The axle 23 on which the wheels 25 are mounted in this case is carried by legs of the U-shaped cap member 33 and is free of the base member 3|, so that the said base member does not prevent the vertical movement of the said cap member. The wheels of the base member are preferably so proportioned that when the said wheels engage the track the lower ends of the legs of the cap member rest on the said base member 3!.

The under side of the upper part of the said cap member 33 is threaded to engage the feed screw H which, in this particular example, has been shown as having a form of thread II in which the thread face opposed to the force imposed thereon by the weight applied to the jack is substantially at right angles to the axis of the screw.

with the construction described in reference to Figures 4 and 5, it will be observed that, by manually lifting the toggle arms and by applying an equal pressure beneath .the table 3| of the jack, the cap members 23 of the blocks may be raised on the guide pins 34 out of engagement with the thread of the feed screw and the said blocks will then be free to ride horiaontally along the guide rod it, under the influence of such upward pressure on the said table, until the said table is brought into contact with the object to be raised. Upon releasing this upward pressure, the weight of the parts will cause the said cap members to descend on the said pins 34 and re-engage the threads of the feed screw, whereupon operation by said feed screw may then be resorted to, to perform the actual lifting function.

Not only does the track member I resist all of the forces other than the end thrust imposed on the feed'screw, but it provides an even surface over which the wheels may travel to assure smooth action throughout the operation of the jack, and also provides an extended surface of relatively considerable area for insuring the firm seating of the Jack on the underlying roadway or bed. In its application to the servicing of automobiles and similar vehicles, the narrow and elongated nature of the said track, permits of its use transversely, longitudinally, or at any angle to the vehicle which conditions may make desirable, and admits of the greatest advantage to be taken of such conditions as are oflered from 'the point of view of stability and convenience of operation of the jack itself.

This invention may be developed within the scope of the following claims without departing from the essential features of the said invention,

, and it is desired that the specification and drawing be read as being merely illustrative and not in a limiting sense, except as necessitated by the prior art.

What I claim is:

1. In a jack, an elongated horizontal guide member, a feed screw parallel thereto, end members longitudinally movable toward and from each other on said guide member by said feed screw, toggle arms swingably connected at their outer ends to said end members, a table commonly connected to the inner ends of said arms, and means on said end members engaging said feed screw, said means being responsive to upward manual movement of said arms to effect their disengagement from said feed screw.

2. In a jack, an elongated horizontal guide member, a feed screw parallel thereto, end members longitudinally movable toward and from each other on said guide member by said feed screw and vertically movable out of engagement with said feed screw, toggle arms swingably connected at their outer ends to said end members whereby said arms by manual upward movement disengage said end members from said feed screw, and a table commonly connected to the inner ends of said arms.

3. In a jack, an elongated horizontal guide member, a feed screw parallel thereto, end members longitudinally movable toward and from each other on and by said feed screw and vertically movable out of engagement with said feed screw, toggle arms swingably connected at their outer ends to said end members whereby said arms by manual: upward movement disengage said end members from said feed screw, guide means for said end members engaging said guide member means limiting the vertical movement of said end members, and a table commonly connected to the inner ends of said arms.

4. In a jack, an elongated horizontal guide member, a feed screw parallel thereto, said end members each including a base portion slidable on said guide rod and a cap portion carried by said base portion, said cap portion engaging said feed screw and being movable vertically relative to said base portion for disengagement with said feed screw, toggle arms swingably connected at their outer ends to the cap portion of said end members, means limiting vertical movement of the cap portion of the said end members, and a table commonly connected to the inner ends of said arms.

5. In a jack, an elongated horizontal guide member, a feed screw parallel thereto, said end members each including a base portion slidable on said guide rod and a cap portion carried by said base portion, said cap portion engaging said feed screw and being movable vertically relative to said base portion for disengagement with said feed screw, toggle arms swingably connected at their outer ends to the cap portion of said end members, means limiting vertical movement of the cap portion of the said end members, a table commonly connected to the inner ends of said arms, a second guide member in the form of a track parallel to said first guide member, and wheels on the cap portion of said end members traveling on said track.

6. In a jack of the type described, a feed screw, end members longitudinally movable toward and from each other on and by said feed screw, latch means on said members gravitationally engaging said feed screw, toggle arms swingably connected at their outer ends to said end members, said screw-engaging latch means being responsive to manual lifting of said toggle arms to effect their disengagement from said end members longitudinally of said teed screw, and a table commonly connected to the inner ends of said arms.

AUGUST RISSAN E. 

